<p>It is the aim of the GBIF data portal to guide users to relevant information on particular species and groups of organisms.  To make this possible, it relies on classification hierarchies shared by its data publishers.</p>

<p>Every dataset within the portal includes information on the names and classifications of the organisms included.  Each species occurrence record includes a scientific name to which the organism was identified, and usually also includes some higher classification -  sometimes the full set of species, genus, family, order, class, phylum and kingdom, but in other cases only a small subset of this information.</p>

<p>The scientific name for an organism may differ depending on the classification used.  In particular, scientific names may change as scientists improve our understanding of the group concerned and species are moved into a different genus, or split into multiple species, or even combined into a single species.  All of these changes can lead to a number of different names being in use for the same set of organisms. These different names for the same organism are called synonyms.</p>

<p>A further variation arises because some datasets are organised around a standard modern classification for the groups concerned (which means that the classification is consistent for all records within the dataset), but other datasets simply report the information that was recorded when the specimen was collected or the observation made. In this case, the same organism may appear under different names or different classifications even within a single dataset.</p>

<p>This means that records for a particular species could be named and/or classified in different ways in different datasets.  To address this problem, the portal makes use of authoritative classifications wherever possible.  It uses these classifications to construct a working structure for the data and seeks to organise other names and classifications into the best place within this structure.</p>

<p>One major source of such authoritative classifications is the <a href="../dataset/provider/2">Catalogue of Life Annual Checklist</a> which brings together scientifically reviewed checklists of different groups of organisms into one overall structure; it currently includes over one million species.  This checklist includes synonyms and common names for many of the species it covers.  The GBIF portal employs this checklist as the core of its own working structure and uses the synonym information to combine records where appropriate.</p>

<p>In addition, the portal uses the <a href="../dataset/provider/3">International Plant Names Index</a> as a source for authoritative information on the names of plants, and the <a href="http://www.speciesfungorum.org/Names/Names.asp">Index Fungorum</a> as a source for authoritative information on the names of fungi.</p>

<p>These resources cover a very large proportion of the species represented in GBIF data.  However, there are still many records that bear names that are not included in these resources.  The portal therefore uses an automated process to try to find the best placement within the hierarchy for each name that does not appear in these indices.</p>  

<p>GBIF recognises that this process is error-prone, and that the results can at best only be tentative, but they do help to increase the probability that users will find records of relevance to their needs, even if the scientific names associated with those records are not included in the Catalogue of Life, the International Plant Names Index or the Index Fungorum.</p>  

<p>Names that have been inserted into the classification through this automated process are shown in grey in the <a href="../species/">Classification Browser</a> and are included in the classification tree under the heading "unconfirmed name".</p>  

<p>The <a href="../species/">Classification Browser</a> allows users to navigate this automatically-generated working structure.  It is also possible to explore the classification used in each individual data resource.  To do this, visit the <a href="dataset">Overview Page</a> for the dataset and select the "Names and classification" link to the right of "Explore" in the blue "Actions" box at the top of the page.  This will open the <a href="../species/">Classification Browser</a> to show just the names and classification used in that particular dataset.</p>

<p>The <a href="../species/">Classification Browser</a> also allows a comparison among classifications for the current species or group of organisms across all datasets included in the portal.  Select the link "Classifications of..." in the pink "Actions" box at the top of the page.  This link opens a tabular view that shows the classification for the current species or group of organisms in all datasets included in the portal.  Click on "view" at the right side of the table to see the whole classification employed within a particular dataset.</p>
